Perfect Zero - Knowledge Arguments for NPCan

\Zero-knowledge arguments" is a fundamental cryptographic primitive which allows one polynomial-time player to convince another polynomial-time player of the validity of an NP statement, without revealing any additional information in the information-theoretic sense. Despite their practical and theoretical importance, it was only known how to implement zero-knowledge arguments based on speciic algebraic assumptions; basing them on a general complexity assumption was open since their introduction in 1986 BCC, BC, CH]. In this paper, we-nally show a general construction, which can be based on any one-way permutation. We stress that our scheme is eecient: both players can execute only polynomial-time programs during the protocol. Moreover, the security achieved is on-line: in order to cheat and validate a false theorem, the prover must break a cryptographic assumption on-line during the conversation , while the veriier can not nd (ever!) any information unconditionally (in the information theoretic sense).